eGRAF® HITHERM™ HT-C3200
eGRAF HITHERM HT-C3200 is a die-cut flexible graphite thermal interface material with in-plane thermal conductivity of 800 W/m·K and through-plane conductivity of 7 W/m·K at 700 kPa. The material delivers thermal impedance of 0.49 K·cm²/W at 200 kPa and 0.18 K·cm²/W at 700 kPa across an operating temperature range of -40°C to +400°C, and its compressibility compensates up to 125 µm of flatness variation between mating surfaces. UL 94 V-0 flammability rated, RoHS compliant, and halogen free.
Key Properties
- Thermal Conductivity @ 700 kPa — In-Plane: 800 W/m·K
- Thermal Conductivity @ 700 kPa — Through-Plane: 7 W/m·K
- Thermal Impedance @ 200 kPa: 0.49 K·cm²/W
- Thermal Impedance @ 700 kPa: 0.18 K·cm²/W
- Operating Temperature: -40°C to +400°C
- Typical Starting Thickness: 200 ± 20 µm / 0.008 ± 0.001″
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Thermal Properties
| Property | Value | Test Method |
| Typical Thermal Conductivity @ 700 kPa — Through-Plane | 7 W/m·K | ASTM D5470 Modified |
| Typical Thermal Conductivity @ 700 kPa — In-Plane | 800 W/m·K | Angstrom’s Method |
| Thermal Impedance @ 200 kPa (29 psi) | 0.49 K·cm²/W | ASTM D5470 Modified |
| Thermal Impedance @ 700 kPa (101 psi) | 0.18 K·cm²/W | ASTM D5470 Modified |
| Operating Temperature | -40°C to +400°C | — |
| Specific Heat @ 25°C | 0.80 J/g·°C | — |
| Coefficient of Thermal Expansion — In-Plane | -0.4 ppm/°C | — |
| Coefficient of Thermal Expansion — Through-Thickness | 27 ppm/°C | — |
Physical Properties
| Property | Value | Test Method |
| Typical Starting Thickness | 200 ± 20 µm / 0.008 ± 0.001″ | — |
| Flatness Variation Compensation | Up to 125 µm | — |
Electrical Properties
| Property | Value | Test Method |
| Electrical Conductivity — Through-Thickness | 5 S/cm | — |
| Electrical Conductivity — In-Plane | 19,000 S/cm | — |
Flame & Fire Performance
| Property | Value | Test Method |
| Flammability Rating | 94V-0 Compliant | UL 94 |
Compliance & Material Composition
| Property | Value | Test Method |
| RoHS Compliant | Yes | — |
| Halogen Free | Yes | — |
Compliance
- UL 94 — Compliant (V-0)
- RoHS — Compliant
- Halogen Free
- IGBT power module thermal interface
- RF device thermal interface in base stations and telecommunications
- UPS, inverter, and motor drive thermal management
- Power supply modules, rectifiers, and chargers
- EV / HEV / PHEV power electronics modules
Common industries: power electronics, telecommunications, electric and hybrid vehicles, high-performance computing, and thermoelectric devices.
eGRAF HITHERM HT-C3200 is a flexible graphite thermal interface material engineered for power module applications that require reliable performance, low contact resistance, long life, and high thermal conductivity.
The flexible graphite construction is die-cut to ensure exact fit and reduce module-to-module variation during assembly, and its compressibility improves surface contact, reducing thermal impedance and compensating for up to 125 µm of flatness variation between the contact surfaces.
Compared to standard graphite TIMs, the defining feature of HT-C3200 is its very high in-plane thermal conductivity of 800 W/m·K, which spreads heat laterally and reduces hot spots in IGBT, RF, and other high-power devices.
Thermally, the material delivers through-plane conductivity of 7 W/m·K and in-plane conductivity of 800 W/m·K at 700 kPa, with thermal impedance of 0.49 K·cm²/W at 200 kPa and 0.18 K·cm²/W at 700 kPa across an operating temperature range of -40°C to +400°C. Thermal impedance reduces significantly with pressure, supporting excellent performance across the pressure ranges common for standard modules and power electronic devices.
Specific heat is 0.80 J/g·°C at 25°C, and the coefficient of thermal expansion is -0.4 ppm/°C in-plane and 27 ppm/°C through-thickness. Electrical conductivity is 5 S/cm through-thickness and 19,000 S/cm in-plane. The typical starting thickness is 200 ± 20 µm (0.008 ± 0.001″); under compression the material thins as pressure increases.
Compliant with UL 94 V-0 flammability, RoHS, and halogen-free requirements. Test methods include Angstrom’s Method (in-plane conductivity at ambient temperature) and ASTM D5470 Modified (through-thickness conductivity and thermal impedance).
What differentiates HT-C3200 from other HITHERM grades such as the HT-1200 and HT-2500 series?
HT-C3200 is positioned for power module service, with the defining feature being a very high in-plane thermal conductivity of 800 W/m·K — substantially higher than the 120 to 150 W/m·K of the HT-1200 and HT-2500 series — which spreads heat laterally and reduces hot spots in IGBT and RF devices. It is also engineered to compensate up to 125 µm of flatness variation between mating surfaces under compression, and it retains the wide -40°C to +400°C operating range of the pure graphite line while remaining halogen free and UL 94 V-0 rated.
Why does thermal conductivity matter in material selection?
The function of a thermal interface material is to move heat from a component to a heatsink with minimum temperature rise. In power modules, both vertical heat extraction and lateral spreading matter — lateral spreading is what eliminates localized hot spots beneath die or package footprints. HT-C3200 provides 7 W/m·K through-plane and 800 W/m·K in-plane at 700 kPa, with thermal impedance dropping from 0.49 K·cm²/W at 200 kPa to 0.18 K·cm²/W at 700 kPa, supporting reliable performance across the pressure ranges common for standard modules.
What is the operating temperature range for HT-C3200?
The operating temperature range is -40°C to +400°C.
Is HT-C3200 suitable for flame-rated, RoHS-regulated, and halogen-free environments?
Yes. HT-C3200 is rated UL 94 V-0 for flammability and is RoHS compliant and halogen free, making it suitable for power electronics, telecommunications, EV/HEV/PHEV modules, and other regulated assemblies.
How should HT-C3200 be specified?
Specify grade (HT-C3200), die-cut part geometry, target interface pressure (which sets effective thickness and thermal impedance), compliance requirements (UL 94 V-0, RoHS, halogen free), dimensional tolerances on the starting thickness (200 ± 20 µm), and finished format.
